Air circulating device



May 16, 193.

F. C. KILB AIR CIRGULATING DEVICE 4 Sheets-#Sheet 1 Filed May 9, 1936May 15, 1939' F. c. KILB AIR CIRCULATING DEVICE Fiied May 9, 1956 4sheets-sheet 2 fa AT RM 0%/ n mc. m E /O V6 m/ May 1s, 1939. F, C KILB2,158,074 l AlR CIRCLATING DEVICE Filed May 9, 1936 4 Sheets-Sheet 5 AyAT RNEY Mayl 1s, 1939.

F. C. KILB AIR CIRCULATING DEVICE Filed May 9. 1936 4 Sheets-Sheety 4 ATORNEY Patented May 1-6, 1939 UNITEDI STATES PATENT OFFICE AIR.CIRCULATING DEVICE Francis C. Kilb, Larchmont, N. Y.

Application May 9, 1936, Serial No. I78,821

13 Claims.

My invention relates to air circulating devices, and more particularlyto devices of this character which eiect circulation of air in roomspaces; such, for example, as a window-mounted ventilator having a fanor blower arranged therein and operating to introduce a stream of freshair into the room space through an air outlet opening in the front ofthe ventilator casing.

It will be appreciated that, as devices of the above type are usuallyinstalled in spaces occupied by people, appearance and neatness areextremely important factors to be considered in their design. As thedevices are operated by all types of individuals, dependability inoperation is also important. Furthermore, low cost of manufacturing andassembling, and low cost and ease of servicing, are also necessary forthe commercial success of the device.

Devices of this type are usually provided with louvers in their airoutlet openings which serve to direct the air owing therefrom to desiredportions of the room and/or serve to close the air outlet openings. Thelouvers should operate easily and simply and remain in any desiredposition: and they should not be mounted in the unit in such a manner asto produce a detrimental effect on the external appearance-of the unit;but, on the other hand, should be mounted in a manner to add to itsexternal appearance. Here.- tofore, louvers have been pivoted directlyto the sides defining the air outlet opening; however, the assembly ofsuch a construction is of necessity a relatively long and tediousoperation, and therefore is relatively expensive. It has also beenproposed to pivotally mount the louvers in a separate frame and attachthe frame to the casing; but structures of this type, heretofore knownto me, are objectionable either because it is extremely p difficult torepeatedly position properly the louvers in the 'air outlet opening, orbecause timeconsuming and expensive operations are required inA properlypositioning the frame with respect to such opening; and also because,after such a frame is mounted in the opening, it is still visible fromthe exterior of the device and therefore detracts materiallys from itsappearance.

My invention has for a broad object to provide an air circulating devicefor use in room spaces, which is of improved construction andarrangement of parts.

Further and more specific objects of my invention are to provideeilicient lo-uver means for an air circulating device which can .beeasily manufactured, assembled, and serviced, and at a low cost; whichcan be quickly and accurately posi.

tioned with respect to the air outlet opening; and one which, in itspreferred form, presents a neat appearance from the exterior of thedevice.

Without imposing any limitation on the invention in its broader aspects,a still further object is to provide an improved form of louverconstruction for air circulating devices which can be readily adjustedtodirect the air to different desired portions of the room and which iseffectively retained at any desired adjusted position.

'Ihe invention consists in the novel construction and combination ofparts, to be more fully described hereinafter, and the novelty of whichwill be particularly pointed out and distinctly claimed.

In the accompanying drawings, to be taken as a part of thisspeciiication, I have fully and clearly illustrated a preferredembodiment of my invention, in which drawings- Fig. l is a verticaltransverse sectional View of a. window-mounted ventilator constructed inaccordance with the present invention, the view being taken on the lineI-I of Fig. 2;

Fig. 2 is a front elevation of the device shown in Fig. 1, drawn on areduced scale; i

Fig. 3 is a perspective View showing the inside of a portion of thefront cover of the ventilator casing with a unitary louver frameassembly removed from the cover to illustrate its construction and modeof assembly;

Fig. 4 is a fragmentary horizontal plan sectional View of thel frontcover of the ventilator casing with the louver frame assembly mountedtherein, the line of the section being indicated by the line -d of Fig.2;

Fig. 5 is a perspective view of the unitary louver frame assemblyshowing the side thereof opposite to that shown in Fig. 3;

Fig. 5 is a perspective view of the louver frame shown in Fig. 5 withthe louver plates omitted;

Fig. 7 is a detail assembly view showing the construction of the louverplates and the pivot rod therefor;

Fig. 8 is an enlarged detail assembly View showing more clearly theunitary link assembly for operating the louver plates in unison; and

Fig. 9 is a view similar to Fig. 6, but showing a modiiied form oflouver frame.

In the accompanying drawings, I have shown my invention as incorporatedin a window ventilator comprising a casing structure lil suitablysupported by a window sill l I and arranged within the opening dened bya partially raised sash l2 and the sill H. The ventilator casing isarranged midway between Window jambs I3, as shown, and suitable fillerblocks I4 serve to close sill II; a top wall 29 having a sealingengagement with the lower rail 2| of the window sash I 2, and having alouver-controlled air outlet 22 in the portion thereof extending intothe room; and end walls 23. The outlet I6 extends for subsnantiauy' thefull length ofthe front wan l5 and is divided in its center by avertical strip 24 into outlet openings 25 and 25a o1 similar size andshape. The inlet opening I8 extends preferably for the full length andheight of the rear wall I1 and rigid louvers 26 are provided on the rearwall for preventing the entrance -into the ventilator of snow and rain.A suitable removable iilter 21 is arranged inside of the ventilator andis disposed across the inlet opening I8 to remove dust particles and thelike from,I the incoming air.

For the purposes of initial assembly, and of removal, repair, andreplacement, the casing i9 is divided preferably into two parts 39 and3|. The part 39 is iixedly mounted in the Window opening and consistsofthe bottom wall I9, the rear wall I1, rear wall parts 32 of the endwalls 23, and rear wall part 33 of the top wall 29, the latter beinghinged at the back as indicated at 34 tol permit insertion and removalof the filter 21. The part 3| is, readily removable as a unit from thepart 39 and comprises the front wall I5, front wall parts 35 of the endwalls 23, and front wall part 36 of the top Wall 29. The part 3| may beappropriately referred to as the removable front cover unit and the part39' as the ixedly mounted base unit.

A partition 31 extends longitudinally of the casing I9 for the fulllength and height thereof and divides the latter into a rear inletchamber 38 communicating with the inlet I8 and an outlet chamber 39communicating with the outlet I6 and outlet 22. .The partition 31 isprovided in itsupper part with an opening 49 connecting thechambers 38yand 39.

-Arranged within the inlet chamber .38 is a removably `mountedmotor-driven blower unit 4| having an inlet 42 communicating with theinlet chambery 38 and an outlet 43 communicating withthe outlet chamber39 through the opening 49 inthe partition 31. A suitable damper Mextends lengthwise of the casing in the outlet chamber 39 and ispivotally supported at its upper end as indicated at-45. The damper inone position provides for the closing of oommunication between the inletand outlet chambers 38 and 39; and, when in another position, forms apart of a tortuous sound deadening passage 46 connecting the opening 49and the outlets I6 and 22. Theopen position of the damper 44 is theposition shown in Fig. i of the drawings.

As stated, the outlet I6 is divided by the strip 24 into the openings 25and 25a. FromI an examination of Figs. 2, 3 and 4, it will be seen thatthe opening 25 is dened by top and bottom edge portions 59 and 5I and byvertical' side edge portions 52 and 53. Likewise, the opening 25a isdene'd by top and bottom edge portions 59a and 5Ia and by vertical sideedgel portions 52a and 53a. The top edge portions 59 and 59a of theopenings 25 and 25a, respectively, are in the same horizontal plane.Likewise,v the bottom.l edge portions 5| and 5|a of the openings 25 and25a are in the same horizontal plane. The edge portions 52, 53, 52a and53a of the openings 25 and 25a are arranged in parallel relation, asshown, with' the edge portions 53 and 52a forming the vertical sides ofthe dividing strip 24.

In accordance with the present invention, I have provided an improvedform of louver means which is carried by the front wall I 5 and forms apart of the removable cover unti 3|. The louver means is mounted in theopenings 25 and 25a forming the outlet I6. This louver means ispreferably so constructed as to direct the air flowing from the casingI9 .to diierent desired `portions of the room, and also serves to closesaid outlet I6, and comprises a frame 55 preferably formed integral withthe front wall I5, and a removable louver frame assembly 56 detachablysecured to he inside of the wall I6.

From an examination of Fig. 3, it will be seen that the frame 55comprises sub-frames 51 and 51a bounding the outlet openings 25arespectively. 'Ihe sub-frame 51 comprises flanges 59 and69 extendinginwardly from the top and bottom edge portions 59 and 5|, respectively,and anges 6I and 62 extending inwardly from the side edge portions 52and 53, respectively. lli'he flanges 59, 69, 6| and 62 are formedintegral with the front wall I5 of the casing and bound the outletopening 25.

Likewise, the sub-frame 51a comprises inwardly extending top and bottomflanges 59a and 69a, and vertical side iianges 6Ia and 62a which areformed integral with the front of the casing and bound the outletopening 25a. A plurality of series of inwardly opening notches 63, 64,63a and 64a are formed in the vertical side ilanges 6I, 62, 6|a and 62afora purpose which will presently appear. 64a forming each series are inhorizontal alinement. v

The louver frame assembly 56 is formed as a unit and is securedremovably to the inside of the front wall I5 by siutable screws 65threaded in openings in brackets 66 suitably fixed, for example by spotwelding, to the front wall I5. The louver frame assembly 56 comprises amain frame 61 and louver plates 68 pivotally mounted in the main frameon horizontally-extending pivot rods 69.

rIn the construction shown in Figs. l, 3, 4, 5 and 6, the main framel 61comprises a top member 19, a bottom member 1I in parallel spacedrelation, end members 12 and 13, and closely spaced intermediate members14 and I5 connecting the mid portions of the top and bottom members 19and 1I to thereby form a rigid rectangular structure. The top member 19is provided with an outwardly-extending iiange 16 of predeterminedwidth. Likewise, the bottom member 1I is provided with an outwardlyextending ange 11 of the same predetermined width as the flange 16. Theend members 12 and 13 and intermediate' members 14 and 15 are providedwith outwardly-extending anges 18, 19, 89 and 8|, respectively, and ofthe same predetermined width as the flanges 16 and 11. The flanges 16,11, 18, 19, 89 and 8| are formed integral with and extend outwardly 4and51a on the front wall of the casing, but

are slightly larger in dimensions.

As can be readily seen from an 4examination The notches 63, 64, 63a andof Figs. 1 and 4, when the louver frame-assembly is in position againstthe inside of the front wall l5, the sub-frames 82 and 82a embrace and tsnugly the sub-frames 51 and 51a, respectively. of the casing. Inassembled position, the outermost edges of the anges 18, 19, 89 and 8lpreferably engage the inside surface of the front wall of the casing;and, as the ilanges are of the same predetermined width, they serve toassure a predetermined position of the louver frame assembly withrespect to such front wall and the openings 25 and 25a. As the flangesforming the sub-frames 82 and 82a. of the louver frame fit andpositively engage the exterior surfaces oi the corresponding fiangesforming the subframes 51 and 51a on the casing, the louver frame ispositively positioned with respect to the outlet openings 25 and 25a andis prevented from displacement in directions parallel to the front ofthe casing and the plane of the outlet openings 25 and 25a. The screws65 passing through the end members 12 and 13 and through screwthreadedopenings in the brackets 85, serve to positively hold the louver frameassembly in position against the inside surface of the front wall i5.

As stated, the louver frame assembly 56 also comprises a plurality oflouvers 68 pivotally mounted on rods 89, said louvers 58 being ar-`ranged in parallel relation to one another within each of vthesub-frames 82 and 82a, and the louvers of one sub-frame are arrangedcoaxial with corresponding louvers in the other subframe. Each of thepivot rods 69 extends horizontally through alined openings in the endvand intermediate flanges 18, 19, and 8| and passes through and issuitably secured to correspondingly positioned louvers in thesub-frames, so that corresponding louvers in the sub-frames move aboutthe same axis and the louvers of each sub-frame move about parallelaxes.

When the louver frame assembly is in place against the inside of thefront wall I5, the louver` plates are disposed within the sub-frames 51and 51a adjacent the openings 25 and 25a, with just enough clearancebetween the ends of the plates and the adjacent flanges to permitpivotal movement of the louvers. Suicient clearance is provided betweenthe ends of the louver plates and the sides of the sub-frames 82 and 82ato permit the location of the side anges of the sub-frames 51 and 51a.between the ends of the louvers and the sides of the sub-frames, 82 and82a. The alined notches 63, 84, 63a. and 84a receive the interveningportions of the pivot rods 69 so as to permit the proper positioning ofthe louvers and frame with respect to the openings 25 and 25a.

Each of the louvers 68 is provided at its end adjacent the verticaldividing strip 24 with an y inwardly extending ange 85. The anges 85 ofall of the louvers are connected together for operation in unison by alink assembly, indicated in general by the reference character 86 (seeFig. 8). The link `assembly comprises a pair of spaced side links 81 and88 connected together by cross pins 89 and 90, the latter being suitablyspot welded tothe side links. 'The side links 81 and 88 are providedwith outwardly-turned end portions 9| which are adapted to t withinopenings-provided in the outer end of the anges 85 of the top and bottomlouvers of each of the sub'- Irames 82 and 82a. The cross pins 89 and 90extend beyond the links 81 and 88 and are adapted to t within openingsprovided in the outer portions of the anges 85 of the intermediatelouvers of the sub-frames. g

An operating lever 93 extends through a slot 94 provided in the dividingstrip 28 in the front wall of the casing, and is suitably pivoted on theintermediate portion of. one of the pivot rods 89, as can be seen froman examination of Fig. 5A The inner end of this operating lever isforked, as indicated at 95, and engages the connecting pin 89 of thelink assembly 88. The opposite end of the operating lever is providedwith a knurled portion 96 which can be grasped by the hand from theexterior of the casing for moving the link assembly up or down and,consequently, the louvers in either direction or to closed position.

An arcuate-shaped spring member 889 is arranged substantially concentricto the arc of movement of the forked end 85 of the operating lever 93and engages the inner end of such lever. The ends of the spring memberIt@ are anchored by screws iti suitably threaded in cross-pieces |92 andi132 secured by spot welding to the intermediate members ll and 'i5 ofthe louver frame. The arcuate-shape spring member |99 is formed von itsconcave side with notches it, 85 and 'it in which the forked end 95 ofthe lever is adapted to fit. By reason of. this construction, the memberi serves as a spring-pressed brake for the operating lever 93 to preventaccidental movement of the lever and louversyand when the forked end tswithin one of the notches in the member |09, the lever is more rmlyheld. The notches are suitably positioned to afford'this extraprecaution against accidental movement at the two extreme positions andat the mid or closed positions of the lever and louvers. In

Fig. 1 of the drawings, one extreme open posi-I tion is shown in fulllines, and the closed position of the louvers and lever is shown indotted f lines.

From the above, it will be readily seen that I have provided an aircirculating device which is of improved construction and arrangement ofparts. form of a separately assembled unit` having the louvers properlypositioned and mounted therein previous to attachment to the casing, andhaving spacing anges of fixed dimensions which are constructed toembrace snuglyv cooperating flanges on the casing, and which engagepositively the inside surface of the front wall of the casing; the

louvers may be at all times properly and quickly positioned with respectto their respective outlet openings and with a minimum requirement oftime. As the inwardly extending flanges of the casing t within theoutwardly extending flanges of the louver frame assembly, no sharp edgesor rough surfaces can be seen from the front of the casing. Therefore,the outlet openings with the louvers properly positioned therein,present a neat and pleasing appearance. Furthermore, the particularmounting of the louvers in the frame with the operating link assembly,operating lever and arcuate-shape spring, provide a louver constructionfor air circulating devices which can be readily and easily adjusted todirect the air to diierent desired portions of the room or to close theopening and which effectively retain the louvers in any desired adjustedposition.

In Fig. 9 of the drawings, I have shown a louver frame which ismanufactured in a diferent' As the louver frame assembly is in the tion.The modified louver frame is indicated at l and comprises an integralone-piece unit, having sub-frames I Il and I l2 formed by flanges I I3vwhich are stamped out of a single piece of metal.

The louver frame shown in Fig. 9 is formed of elements which functionidentically with the elements of the one shown in Fig. 6, the onlydifference being that the one shown in Fig. 6 is formed of angle piecesspot welded together, and the one shown in Fig. 9 is a single stamping.The construction of Fig. 9 may beless expensive than the constructionpreviously described, should the units be made in sufdciently largequantities to j'ustify the initial cost of the dies for stamping.

What I claim and desire to secure by Letters Patent of the United Statesis:

1. An air circulating device for use in room spaces, comprising wallsdefining a casing; one wall of said casing having an air openingtherein; flanges extending inwardly ofy the casing from the edges deningsaid opening; a louver frame arranged within said casing adjacent saidopening and behind said flanges so that the frame is concealed by theanges; and louvers carried by said frame and extending across saidopening for controlling the ow of air through said opening.

2. An air circulating device for use in room spaces, comprising a casingincluding a wall structure, one wall of which is provided with anopening; a louver frame arranged inside of said casing and adjacent thesides of said opening and including outwardly directed flanges engagingat their outer edges the inside surface of said one wall; louverscarried by said flanges andy extending across said opening; and flangesextending inwardly'of said casing from the defining edges of saidopening and overlapping and concealing the anges of said louver frame.

3. An air circulating device for use in room lspaces, comprising acasing including a. wall structure, one Wall of which is provided withan opening; a louver frame arranged inside of said casing; louverspivotally mounted at their ends to said frame and extending across saidopening;

flanges extending inwardly from the dening edges of said opening andconcealing said louver frame; said flanges having inwardly-openingvnotches receiving the pivotal mountings for said louvers.

4. An air circulating device for use in room spaces, comprising a casingincluding awall structure,`one wall of which is provided with anopening; positioning flanges extending inwardly of the casing from theinside dening edgesof the.

opening; and a louver frame assembly arranged interiorly of said casingand having outwardly extending flanges engaging the surfaces of saidcasing flanges which are remote from the opening so as to position thelouver frame assembly positively with respect to said opening.

5. An air circulating device for use in room spaces, comprising a casingincluding a wall structure, one wall of which is provided with anopening; flanges rigid with said wall and projecting inwardly into thecasing from opposite edges of Y said opening; a unitary louver structurearranged within said casing and adjacent said opening and including aframe member conforming substantially to the contour of said opening;said frame member including opposite frame elements 1ocated respectivelyon the sides of said flanges which are remote from said opening; andlouver plates pivoted in said frame elements and extendving across saidopening; said louver frame having parts projecting outwardly therefrominto engagement with the interior surfaces of said wall.

6. An air circulating device for use in room spaces. comprising a casingincluding a wall strucwithin said casing and adjacent said opening andincluding a frame member conforming substantially to the contour of saidopening; said frame member including opposite frame elements lo-,n catedrespectively on the` sides of said flanges which are remote from saidopening; and louver plates pivoted in said frame elements and extendingacross said opening; said louver frame having parts projecting outwardlytherefrom into engagement with the interior surfaces of said wall.

and engaging at their inner side surfaces the surfaces of said flangeswhich are remote from said opening.

7. Anair circulating device for use in room spaces comprising wallsdefining a casing structure; one of said walls having an air opening 2otherein; frame means rigid with said casing and comprising positioningange members extending interiorly of the 'casing from the inside edgeportions of said opening and being disposed at opposite sides of theopening; and a louver frame assembly secured to the casing at the insidethereof and comprising a louver frame member similar in shape to saidcasing frame means and slightly larger in dimensions, and a plurality oflouver plates pivotally mounted at their opposite 3u ends to the louverframe member; said louver frame member including outwardly extendinglportions receiving the pivotal mountings for the louver plates and beingarranged at the outside of and engaging the sides of said ange members,:is

and abuttingv the inside surfaces of the casing.

8. An air circulatingfdevice for use in room spaces, comprising wallsdefining a casing structure; one of said wa'lls having an air openingtherein; frame meansrigid with said casing and 4o comprising positioningflange members extending interiorly of the casing from the inside edgepor# tions of said opening and being disposed at opposite sides or' theopening; and a louver frame assembly secured to the casing at the insidethereof and comprising a louver frame member similar in shape to saidcasing frame means and slightly'larger in dimensions, and a plurality oflouver plates pivotally mounted at their opposite ends to the louverframe member; said louver frame member including outwardly extendingportions receiving the pivotal mountings for the louver plates and beingarranged at the outside of and, engaging the sides of said ange members.

9. An air circulating device for use in room v spaces, comprising wallsdening a casing structure; one of said Walls having an air outletopening therein having pairs of opposed sides; casing frame meanscomprising positioning flanges formed integral .with said one casingwall and 6|" extending interiorly of the casing from the in;- side edgesof said opening, there being a flange at each side of the opening andextending for the full length thereof, and the anges being arranged inplanes normal to the plane of the outlet opening; one pair of theoppositely disposed flanges having alined notches formed therein andopening inwardly of said casing; and a louver frame assembly secured tothe 'casing at the inside thereof'and comprising a frame member similar70 in shape to the casing frame means and slightly larger in dimensions,a plurality of louver plates, and means for pivotally mounting theplates at their opposite ends to the louver frame memben" said louverframe member including outwardly 'I6 extending portions arranged at the;opposite side of and engaging the sides of the casing flanges and havingtheir outermost edges abutting the inside surfaces ofthe casing wherebythe louver frame, with the louver plates mounted therein,

is positively positioned (in directions both lateral and normal to theplane of the outlet opening;

'l slightly larger thanI the aforementioned rectangular frames; saidframe structure .being arranged at the inside of the casing with itoutwardly extending flanges embracing and fitting snugly about therectangular frames on the casing and having the outer edges of itsoutwardly extending iianges engaging the inside of the said pivotalmounting means comprising pivot casing to( properly position the louverframe l rods extending from the, ends of the louver plates through thealined notches in the casing frame ilanges and being secured at theirouter ends to the outwardly extendlngportions of the louver w frame.

10. A n air circulating device for use in room spaces, comprising acasing including a wall having an air outlet opening; flanges extendinginteriorly of the casing from said wall and bounding said outlet openingto provide a frame rigid with the wall and at the inside ofthe opening;said flanges having a plurality of relatively deep inwardly openingnotches vformedV thereinland disposed at opposite sides of the openingwith each of the notches being in alinement with a corresponding notchon the opposite side of the sopening; 'a louver framehaving an openingof substantially the same configuration as said outlet opening andhaving slightly larger dimensions;

said louver frame including outwardly extending 1 anges formed rigidwith the louver'irame and boundingthe opening therein; said louver frameiianges embracingand iltting snugly about the casing iianges andengaging at their outer edges `the inside surfaces of the casing; pivotrods ex- `tending across the openings and through said aimed notches andsecured at their opposite" ends in the louver trame flanges; a pluralityof louver plates arranged within the space defined by the casing flanges'and vextending across such space from one side to the opposite sidethereof and each plate being pivotally mounted on one of the pivot rods;and means for'securing the louver frame to the casing wall.

11. An air' circulgting device for useiln room spaces, comprising acasing having a pair of rectangular-shaped openings .oi substantiallythe same dimensions and being disposed in side-byf side relation with arelatively'thin strip of casing structure therebetween and with one pairof the opposed sides of one opening arranged in the same planes as thecorresponding sides of the other openingy and with the other pair oi'op:- posed sides of said'one opening disposed parallel to thecorresponding sides of the other opening;

anges formed integral with said casing and extending`v inwardly fromeach side edge oi'each of the openings to provide a pair bi rectangular.frames coextensive with their respective openings at the inside thereof;a louver frame assembly comprising a frame structure includingKoutwardly extending flanges disposed in the' form or a pair ofrectangles 'of the same shape and withP one pair of the opposed sides ofone of the openings arranged in the same planes as the Y correspondingsides of the other opening and with the remaining sides of the openingsarranged y in parallel relation to one another; flanges extendingoutwardly freni one side oi the l body member at each side edge of eachYof the openingsto provide a pair of rectangular subframes coextensivewith their respective openings; a plurality of parallel equally spacedpivot lli rods extending across both openings and connected to the angesof the sub-frames; and louver plates Jpivotally mounted on the rodswithin each of the openings.

13. An air circulating device for usein room spaces, comprising a casinghaving an opening therein; av plurality of parallel louvers extendingacross the" opening and pivotally connected at `their ends to oppositedefining edges of the opening so as to move about parallel axes; aflange member extending from each of the louvers inwardly from thecasing at one side of the openl ing; link means connecting the ilangemembers for moving the louvers in unison; an operating pin connected tothe ange of one of the louvers and arranged parallel to its axis ofmovement; an operating lever mounted for pivotal movement about an axisparallel to said pin and having a slotted end engaging said pin; and an@arcuate-shaped spring member disposed substantially concentric with theaxis of movement of 'the slotted end of the lever and being inengagement with the latter; said spring member being Vanchored at itsends at opposite sides of the slotted end of the lever and havingspaced-apart notch portions therein, in which the slotted end of thelever is adapted to nt and be resiliently j held thereby 'whfgi atpredetermined positions.

" FRANCIS C. KILB.

